1. Field of the Invention
The present invention is directed to an apparatus for washing spray guns with a liquid solvent, and more particularly to an apparatus for washing paint spray guns and associated component parts with a liquid solvent and including means for recycling the solvent to provide purified solvent for subsequent cleaning operations.
2. Description of the Related Art
Paint spray gun assemblies have long been used in various painting operations, particularly in the automobile and marine industries. Typically, a paint spray gun assembly includes a hand-held spray gun and a can or cud which attaches to the gun for holding paint to be supplied to the gun for spraying therefrom. Generally, paint spray gun assemblies include two types of systems. These include siphon spray guns for use with small scale jobs in which a small amount of paint is required, and pressure spray guns which are usually used for large scale jobs requiring a significant amount of paint. The use of such equipment is primarily to enable rapid painting of objects. After use of the spray gun assembly during a particular job, the entire assembly, including the gun, cup and associated component parts must be thoroughly cleaned of the paint which accumulates both on the interior and exterior surfaces of the equipment. Cleaning of the equipment is required not only to prevent mixing of colors, which may result in an undesirable color blend, but also to prevent buildup, blockage and jamming of the equipment. Obviously, in a commercial environment, such as a paint workshop, the need to clean the equipment on a regular basis entails a great deal of time and expense. Usually, a paint workshop, such as an automotive paint shop, will use numerous spray gun assemblies throughout a daily painting operation. In this instance, it will usually be required to clean a number of spray gun assemblies on a daily basis, and possibly several times a day if the assemblies are used with different paint colors.
In an attempt to minimize the time and expense associated with cleaning a large number of spray gun assemblies on a daily basis, there has been developed various spray gun washers which are designed to circulate a cleaning fluid through a flow-line system for ejection of the fluid under pressure within a closed cabinet. An example of such an apparatus is disclosed in the U.S. Patents to Yamamoto, U.S. Pat. No. 4,785,836 and Robb et al., U.S. Pat. No. 4,793,369. The spray washer apparatus disclosed in these patents generally comprise a cabinet or housing divided into a work chamber and a fluid storage reservoir containing paint solvent and water. The solvent and water mixture is pumped from the storage reservoir to spray nozzles located in the work chamber. The paint spray gun and can are supported in the cleaning chamber such that the paint passage interior of the gun is in direct fluid flow communication with the fluid outlets. Thus, during cleaning, the solvent in Dumped from the storage reservoir out through the nozzles to clean the exterior of the spray gun and can and also through the gun and within the inside of the can to clean the inner surfaces thereof. The contaminated solution then returns to the storage reservoir for subsequent use. After a period of time, the contaminated solution is drained from a bottom of the storage reservoir by opening a valve, and fresh cleaning solvent are replaced within the reservoir. While these spray washers have been found to be effective for use in washing spray guns and associated parts, they do not provide for recycling and purifying of the cleaning solvent. Therefore, the contaminated solvent must be disposed of on a regular basis while complying with E.P.A. disposal guidelines. This disposal process can prove to be inefficient, costly and therefore, most paint workshops using this washing equipment tend to reuse the cleaning solution for an extended period of time, resulting in the use of contaminated cleaning solvent/solution being used during cleaning operations.
There has been developed a cleaning apparatus for cleaning painted parts which provides for the recycling of the cleaning solvent. Such an apparatus is disclosed in the U.S. Patent to Ihringer, U.S. Pat. No. 4,407,316 directed to a cleaning installation comprising a treatment chamber in which the painted parts are cleaned and exposed to jets of a mixture of hot water and cleaning solvent. The installation, as disclosed in Ihringer includes a plurality of individual separating chambers for separating light paint solvents, cleaning solvent of paint, water cleaning solvent and gas cleaning solvent. This type of cleaning installation is somewhat complex, use a series of separating chambers, requires a significant amount of space and is generally cost prohibitive for most paint workshop environments.
Accordingly, there is a definite need in the spray gun art for a washing apparatus specifically designed for washing both the exterior and interior surfaces of paint spray guns, paint cans and associated component parts with a solvent, such as paint thinner, wherein the apparatus provides means for recycling the solvent to provide pure, continuous "on demand" fresh solvent. Such an apparatus eliminates the disposal and replacement problems normally associated with paint spray gun washers while providing a practical means of complying with E.P.A. disposal guidelines.